(1R)-N-prop-2-ynyl-2,3-dihydro-1H-inden-1-amine (I) also termed as Rasagiline or (R)N-propargyl 1-indanamine is an irreversible inhibitor of monoamine oxidase used as a monotherapy in early Parkinson's disease or as an adjunct therapy in more advanced cases.

Racemic propargyl-1-aminoindan hydrochloride was described in GB1003686, GB1037014, U.S. Pat. No. 3,513,244. In the prior art the racemic mixture of propargyl-1-aminoindane was prepared by reacting 1-chloroindane or 1-bromoindane with propargylamine.
The R-enantiomer of rasagiline was described in EP0436492 and EP0812190 and the process disclosed comprises reacting optically active R-enantiomer of 1-aminoindan with propargyl bromide or propargyl chloride in presence of an organic or inorganic base and optionally in the presence of a solvent.
U.S. Pat. No. 5,532,415 discloses rasagiline R(+)-N-propargyl-1-aminoindan, its preparation, and various pharmaceutically acceptable salts thereof. U.S. Pat. No. 5,532,415 discloses that an enantiomerically pure aminoindan derivatives may be obtained by optical resolution of racemic mixtures of R- and S-enantiomers of propargyl aminoindan derivatives. Such a resolution can be accomplished by any conventional resolution method well known to a person skilled in the art. For example, the resolution may be carried out by preparative chromatography on a chiral column.
U.S. Pat. No. 5,532,415 further describes how an enantiomerically pure propargyl aminoindan can also be prepared directly from the optically active R-enantiomer of 1-aminoindan by reaction with propargyl bromide or propargyl chloride or a propargyl sulfonate ester in the presence of an organic or inorganic base, like triethylamine, pyridine, alkali metal carbonates, and bicarbonates and optionally in the presence of a suitable solvent chosen from, e.g., toluene, methylene chloride, and acetonitrile.
The process for preparation and separation of aminoindan derivatives described in the prior art have their shortcomings. Chromatography is difficult to scale up because of the large quantities of solvents used, which are difficult to dispose of. It is very difficult to carry out distillation of the high boiling aminoindan derivatives. Further use of propargyl chloride or bromide is a very difficult because it is highly toxic flammable liquid. It is decomposed explosively with shock and heat hence is not suitable for an industrial scale up.
The aim of the present invention is to provide an alternative and improved process which helps to overcome the shortcomings associated with the prior art processes.